<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8" />
  <title>popup</title>
</head>

<style>
  label {
    font-size: 20px;
  }
  input[type="checkbox"] {
    width:30px;
    height:30px;
  }
</style>

<body style="width:320px;min-height:240px;">

  <label>
    <input type="checkbox" id="jsSwitch">
    JavaScript开关
  </label>
  <script type="text/javascript" src="js/popup.js"></script>
</body>

</html>